Aromatic polyisocyanate prepolymer based on diphenylmethane diisocyanate (MDI). (A) As a binder for the formulation of moisture-curing, one-component coatings and adhesives. (B) As a hardener for hydroxyl-bearing co-reactants. Properties / Applications: Desmodur® E 21 is suitable for use in the formulation of moisture-curing one-component systems which, when thinned with a suitable solvent, can be used as a primers and sealers for porous substrates to provide protection against moisture, oil, fuel and other chemicals. It can also be used as a binder in the formulation of synthetic resin mortars. In combination with suitable Desmophen polyols, Desmodur® E 21 yields tough but flexible, wear-resistant coatings and sealers. Desmodur® E 21 is also suitable for use in the formulation of solvent-free moisture-curing one-component adhesives or in combination with Baycoll® to formulate two-component adhesives. These can be used to bond many materials, e.g. wood, metal and plastic. Information provided by Covestro |